RU2373605C1 - Method of making optoelectronic microassemblies - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to production of microeletronic devices in form of microassemblies, which consist of semiconductor devices and microchips on a solid state-body, formed on a single common insulating substrate, which contains semiconductor components which are sensitive to light and are specially designed for controlling energy of electrical signals, which constitute the data stream to be processed in accordance with the operation algorithm of the microassembly.

EFFECT: wider functional capabilities of the microassembly made using the proposed method.

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Description

The invention relates to the production of microelectronic devices for private use in the form of microassemblies [1, p.13, p.325; 2, p. 9, p. 10, fig. 1.1], consisting of semiconductor devices and solid-state microcircuits, formed on one common dielectric substrate containing semiconductor components that are sensitive to light and specially designed to control the energy of electrical signals that make up information the stream to be processed in accordance with the microassembly functioning algorithm.

Known [3, p.3] the main advantages inherent in electronic-optical devices, namely: ideal electrical isolation of the inputs and outputs of devices; secrecy of information transmission through an optical communication channel; high noise immunity of optical communication channels, which helps to increase the reliability of digital microelectronic devices under the influence of destabilizing factors. To transmit information signals in optoelectronic devices in the form of optical radiation pulses propagating through a light guide from a transparent immersion medium from a radiation source (eg, an LED) to a photodetector (eg, a photodiode), various optoelectronic devices are used: optocouplers, optocouplers, wristrons, etc. [ 3, p.122, p.124, fig.5.1, fig.5.2], which contain LEDs and photodiodes interconnected through a transparent light channel in a single device design.

A known method of manufacturing optoelectronic nodes, made in the form of a bulk optoelectronic module and base with a control module [4]. In the manufacture of the node by this method, optical fibers and U-shaped couplers are placed inside the base, which are connected by zigzag couplers equipped with optical switches. The cavities of the optical fibers and U-shaped splitters are filled with liquid crystal material and optical fiber. The inputs and outputs of the optoelectronic node are in the form of base windows; in which receiving and light-emitting elements are placed. LEDs and photodiodes are mounted on the mounting surface of the base, respectively, with light emitting and photo-receiving surfaces facing the mounting surface of the base.

The disadvantage is the limited functionality of the nodes manufactured by this method, due to the significant sensitivity of liquid crystal materials to the destabilizing effect of high and low temperatures, magnetic fields, ionizing radiation and other external factors.

A known method of manufacturing optoelectronic devices in the form of functionally complete printed units, in which the electronic and optical components are placed on a switching base made using printed circuit technology [5]. According to this method, on the surface of a printed circuit board (made using printed wiring technology from foil textolite, getinax or fiberglass), they are mounted using soldering, welding or other packaged microcircuits, the information output buses of which are connected to the information input buses of other microcircuits by means of optocouplers, optocouplers or volstrons. In this case, for example, a reflective layer is applied to one of the surfaces of the optical channel inside the structure of the optocoupler, eliminating the possibility of branching of the transmitted optical signal [3, p.125, Fig. 5.3, d].

The disadvantage is the limited functionality of optoelectronic devices made using printed circuit technology, due to the inability to branch optical information signals propagating in a closed transparent optical channel of optocouplers.

The closest in technical essence to the proposed one is a method of manufacturing optoelectronic devices using hybrid technology [1, p. 322, p. 324, fig. 14.8, p. 418]. In the manufacture of an optoelectronic device by this method, digital integrated circuits and optoelectronic devices (optocouplers) are mounted on a ceramic or glass substrate [1, p. 54, Fig. 3.1; 6, p. 85, tab. 8.1] inside the microassembly body [2, p. 10, fig. 1.1].

The manufacturing process of the optoelectronic device by a known method includes:

- topological calculation of seats for placing microcircuits and optocouplers on the mounting surface of the substrate and calculation of the geometric dimensions of the contact pads and electrical conductors between them [6, p.111, p.133, p.178, p.203, p.212];

- manufacture of a glass substrate with polished surfaces [1, p. 54];

- drawing on the mounting surface of the substrate of the contact pads and electrical conductors between them using thin-film technology [1, p. 418, p. 420, p. 421, table 19.1; 6, p. 83, p. 87];

- installation of microcircuits and optocouplers on the corresponding seats of the mounting surface of the substrate [1, p. 322, p. 324, fig. 14.8, p. 418];

- installation of the substrate in the housing of the microassembly [1, p. 52, p. 314, p. 322, p. 326, Fig. 14.11; 2, p.10, fig.1.1].

The disadvantage of this method is the limited functionality of optoelectronic devices in the form of microassemblies made using the known hybrid thin-film technology, due to the impossibility of branching optical information signals propagating in a closed transparent optical channel of the optocouplers from the output information bus of one microcircuit to the input information bus of another adjacent microcircuit.

The task of the invention is to expand the functionality of the microassembly manufactured by the proposed method.

The problem is solved in that in a method for manufacturing an optoelectronic microassembly containing a housing with digital integrated circuits mounted on its glass substrate, the corresponding information output and input buses of which interact via beams of pulsed light radiation propagating from LEDs to photodiodes, including topological calculation of the seats for placement of microcircuits, LEDs and photodiodes on the upper mounting surface of the substrate and geometric measures of the contact pads and electrical conductors between them, the manufacture of a glass substrate with polished surfaces, the application of thin-film contact pads and electrical conductors between them on the upper mounting surface of the substrate, the installation of microcircuits, LEDs and photodiodes on the corresponding seats on the upper mounting surface of the substrate and the installation of the substrate in the housing microassemblies, when performing a topological calculation, additionally determine the location on the upper and lower surfaces x the substrate of mirrors with a reflecting surface facing the glass, and designed to reflect a beam of electromagnetic light radiation propagating in accordance with the optical connection scheme through the glass substrate from the LED to the interacting photodiode, and the angles of incidence of the radiation beams on the substrate for each LED spot are calculated, optically coupled to respective photodiodes. After the manufacture of a glass substrate with polished surfaces, it is applied to its upper and lower surfaces in accordance with the results of a topological calculation of the location of the mirrors on the surfaces of the substrate. Then, after applying thin-film contact pads and electrical conductors between them onto the upper surface of the substrate, the glass substrate is subjected to radiation tinting by electromagnetic x-ray or gamma radiation at a dose of 10 ² ... 10 ⁴ Gy. Then, beams of sharply focused pulsed or continuous laser processing radiation are transmitted sequentially through each of the seats of the LEDs through the glass substrate at appropriate angles of incidence on the glass with a focal length many times greater than the length of the substrate and an energy of 25-50 mJ for a period of time sufficient to form in the glass the substrate of a transparent light-conducting communication channel between the corresponding pair of interacting LEDs and photodiodes. At the same time, mirrors are applied discretely to the lower and upper surfaces of the substrate in accordance with the results of topological calculation of the locations of the mirrors on the lower and upper surfaces. In addition, a continuous mirror layer is applied to the lower surface of the substrate, and mirrors are applied discretely to the upper surface of the substrate in accordance with the results of topological calculation of the locations of the mirrors on the upper surface of the substrate, and thin-film technology, such as aluminum, is used as mirrors.

The invention is illustrated by drawings:

figure 1 is a fragment of the structure (section) of the optoelectronic microassembly with discrete mirrors on the upper mounting surface of the substrate and a continuous reflective layer on the lower surface of the substrate;

figure 2 is a fragment of the structure (cross section) of the substrate after the operations of applying to the glass thin-film discrete mirrors, pads and electrical conductors and the subsequent operation of radiation tinting (darkening) of the glass;

figure 3 - diagram of the formation of a beam of laser radiation, for example, the first transparent light-conducting channel in a radiation-tinted glass substrate;

4 is a diagram of the formation by a laser beam of a second transparent light guide channel in a radiation-tinted glass substrate.

The drawings indicate: 1 - the cover of the microassembly; 2 - the base of the microassembly; 3 - glass substrate of thickness b (radiation-tinted region); 4 - transparent (illuminated) light guide channels in a glass substrate; 5 - glue (adhesive compound); 6 - upper mounting surface of the substrate; 7 - lower mounting surface of the substrate; 8 - a continuous reflective (mirror) layer on the lower surface of the substrate; 9 - contact pads and film electrical conductors; 10 - discrete mirrors on the upper mounting surface of the substrate; 11 - crystals of digital integrated circuits; 12 - electrical leads, for example, ball, microcircuits; 13 - LED connected to the information output bus of the chip; 14 - photodiodes connected to the information input buses of microcircuits; 15 - the optical axis of the propagation of the light beam of signal radiation through a transparent light-conducting channel of the glass substrate from the LED to the photodiodes; 16 - discrete mirrors on the lower mounting surface of the substrate; 17 - a technological laser (a source of laser processing radiation); 18 - optical axis of the beam of the laser processing radiation; Хпmi - coordinates along the abscissa axis of the seats of LEDs and photodiodes; Хвзi - coordinates along the abscissa axis of discrete mirrors on the upper mounting surface of the substrate; Хнзi - coordinates along the abscissa axis of discrete mirrors on the lower mounting surface of the substrate, where i is the serial number; ά1 is the angle of incidence of the laser processing radiation on the glass surface of the substrate during the formation of, for example, the first transparent light-conducting channel; β1 is the angle of refraction of the laser processing radiation in the glass during the formation of the first transparent light-conducting channel; ά2 is the angle of incidence of the laser processing radiation on the glass surface of the substrate during the formation of the second transparent light-conducting channel; β2 is the angle of refraction of the laser processing radiation in the glass during the formation of the second transparent light-conducting channel; φ is the angle of reflection of the light beam (laser processing or signal radiation) from the mirror surface of the reflective layer.

The coordinates of the discrete mirrors 10, 16 and the seats of the LEDs 13 and photodiodes 14 along the ordinate axis in the drawings of figures 1 ... 4 are not shown conditionally.

The order of operations of the proposed method for manufacturing an optoelectronic microassembly is as follows (see additionally, drawings 1 ... 4):

1) Perform a topological calculation of the seats for the placement of microcircuits 11, LEDs 13 and photodiodes 14 on the upper mounting surface 6 of the substrate 3 and the geometric dimensions of the contact pads 9 and electrical conductors 9 between them in accordance with the physico-topological models of the elements [6, p. 111 , p.133, p.178, p.203, p.212].

Additionally, coordinates are calculated on the abscissa and ordinates of the locations on the upper 6 and lower 7 surfaces of the substrate 3 of the mirrors 10, 16 with a reflective surface facing the glass 3, and designed to reflect the beam of electromagnetic light radiation 15, propagating in accordance with the optical connection scheme through glass substrate 3 from the LED 13 to the interacting photodiodes 14.

When determining the location of the LED 13 (see figure 1), the optical radiation 15 of which is distributed through separate transparent communication channels 4 with several photodiodes 14, a topological calculation must be carried out taking into account the radiation pattern of the LEDs 13 [3, p.13, p. 17, p.18, fig.2.2, d, fig.2.3, d, s.19, fig.2.5, d].

The geometric size of the plane of each of the mirrors 10, 16 should provide a reflection of the entire beam of optical signal radiation 15 propagating through the transparent light-conducting channel 4 of the optical communication of the LEDs 13 and their corresponding photodiodes 14.

In addition, the angles of incidence άi on the substrate 3 of the radiation beams (laser processing 18 and signal light 15) are calculated for each seat of the LEDs 13, which are optically coupled to the corresponding photodiodes 14.

The topological calculation and calculation of the elements of the optical interaction scheme of the LEDs 13 and photodiodes 14 are performed in accordance with the basic laws of geometric optics, taking into account the thickness b of the glass substrate 3 [7, p. 261, fig. 229, p. 226, fig. 230].

When performing topological calculations, specialized software and design automation tools are used [6, p.214] - computers;

2) A glass substrate 3 is made, for example, by cutting from a sheet blank with parallel polished upper 6 and lower 7 mounting surfaces [1, p. 54]. The thickness b of the glass substrate should correspond to the data of a topological calculation of the parameters of the elements of the optical interaction scheme of the LEDs 13 and photodiodes 14, made in accordance with the basic laws of geometric optics [7, p. 261, fig. 229, p. 226, fig. 230];

3) Apply by thin-film technology [1, p. 418, p. 420, p. 421, table 19.1; 6, p.83, p.87] on the upper 6 and lower 7 polished surfaces of the glass substrate 3 mirrors 8, 10, 16, for example, aluminum with a thickness of not more than 12 microns [8, p.176] in accordance with the data of topological calculation the location of the mirrors 10, 16 on the surfaces of the substrate 3 and their sizes;

4) Apply by thin-film technology [1, p. 418, p. 420, p. 421, table 19.1; 6, p.83, p.87] on the upper surface 6 of the glass substrate 3 contact pads 9 and electrical conductors 9 between them, for example, from copper and other metals [8, p.176] in accordance with the data of the topological calculation of contact pads 9 and electrical conductors 9;

5) Subject the glass substrate 3 to radiation tinting by electromagnetic x-ray or gamma radiation with a dose of 10 ² ... 10 ⁴ Gy [9, p.273; 10. p. 37].

In this case, the darkening of glass 3 occurs (the glass acquires a golden brown hue) and the optical density (refractive index) of radiation-tinted glass 3 increases (for example, to the value of nton = 1.52 compared to the refractive index of transparent glass npr = 1.50) [9, p. 273, p. 279, fig. 82, p. 282, pl. 248, pl. 249, p. 283, pl. 252; 10.C.41; eleven];

6) The glass substrate 3 is exposed to a beam of sharply focused pulsed or continuous laser radiation 18 (the focal length of the output lens of the laser 17 should be many times greater than the length of the formed transparent light guide channel 4, that is, be much longer than the substrate 3).

The wavelength of the laser processing radiation 18 should be less than 2.5 μm, i.e. correspond to the transparency range of glass [12, p. 9, fig. 1, p. 10]. For example, to be equal: 1.06 microns (solid-state laser - neodymium in glass); 0.53 ... 0.55 microns (activators - rare earth elements); 0.69 μm (ruby); 0.85 μm (semiconductor laser) [13, p. 27 ... 28, p. 160, table 25; 14, p. 39, table 4]).

The wavelength of the laser processing radiation 18 should correspond to the wavelength of the light signal radiation 15 of the LEDs 13 to be mounted on the glass substrate of the manufactured microassembly.

The energy of the processing radiation is from 18 to 50 mJ [13, C.305 ... 313].

The angle паденияi of incidence of the laser processing radiation 18 on the surface 6 of the glass 3 should provide refraction of the beam at an angle less than the limiting [7, p.305] and correspond to the calculation data of the elements of the optical interaction scheme of the LEDs 13 and photodiodes 14 in accordance with the basic laws of geometric optics, taking into account the thickness b glass substrate 3 [7, p. 261, fig. 229, p. 222, fig. 230], made according to claim 1 (see above).

A beam of pulsed or continuous laser processing radiation 18 is passed through a glass radiation-tinted substrate 3 for a period of time up to 60 s (during the formation of each of the channels 4).

The time of laser processing of the substrate 3 is determined by the duration of the formation of a narrow channel [4, p. 373] in the glass 4. As a result of laser treatment, the transparency of the glass is restored [10, p. 38; eleven].

When forming the illuminated channel 4 in the radiation-tinted glass substrate 3 (see FIGS. 3 ... 4), the transparency of the glass is restored along the propagation axis of the laser radiation 18. The diameter of the formed transparent channel 4 is determined by the diameter of the beam of the laser processing radiation 18 in accordance with the Gaussian distribution law radiation power in the cross section of the light beam, and the interface between the radiation-tinted 3 and transparent 4 regions of the substrate is clearly defined [10; eleven];

7) Carry out the installation of microcircuits 11, LEDs 13 and photodiodes 14 on the corresponding seats of the mounting surface 6 of the substrate 3 [1, p. 322, p. 324, fig. 14.8, p. 418];

8) Carry out the installation of the substrate 3 in the housing of the microassembly, including fixing the substrate 3 on the base 2 of the housing, for example, using glue 5, electrical installation of the leads of the substrate 3 with the leads of the housing and welding of the cover 1 to the base 2 of the housing [1, p.52, p .314, p. 322, p. 326, fig. 14.11; 2, p.10, fig.1.1].

Thus, the proposed method for the manufacture of optoelectronic microassemblies compares favorably with the known ones, since it provides the possibility of implementing optical communication of each of the information buses of the microcircuits with several input information buses of other microcircuits, which significantly expands the functionality of processing information flows in optoelectronic microassemblies.

Used sources

1. Chernyaev V.N. Technology for the production of integrated circuits and microprocessors: A textbook for universities. 2nd ed., Revised and add. - M.: Radio and communications, 1987. - 464 p.: Ill.

2. The layout and design of microelectronic equipment: Reference manual / P.I. Ovsisher, I.I. Livshits, A.K. Orchinsky et al. / Ed. B.F. Vysotsky, V. B. Pestryakova, O. A. Pyatlin. - M .: Radio and communications, 1982. - 208 p.: Ill.

3. Bystrov Yu.A. and other Optoelectronic devices in amateur radio practice: Ref. allowance / Yu.A. Bystrov, A.P. Gapunov, G.M. Persianov. - M .: Radio and communications, 1995 .-- 160 p .: ill.

4. Patent RU No. 2158020, IPC G02F 3/00. Optoelectronic node / Mokryshev V.V., Mokryshev S.V. - Declared 10/01/1999. - Publ. 10.20.2000. (analogue).

5. Gorobets A.I. and other Handbook on the design of electronic equipment (printing units) / A.I. Gorobets, A.I. Stepanenko, V.M.Koronkevich. - Kiev: Technique, 1985 .-- 312 p.: Ill. (analogue).

6. Berezin A.S., Mochalkina O.R. Technology and design of integrated circuits: Textbook. manual for universities / Ed. I.P. Stepanenko. - M .: Radio and communications, 1983. - 232 p .: ill. (prototype).

7. Trofimova T.I. Physics Course: Textbook. manual for universities. - M .: Higher. school, 2001 .-- 542 p.: ill.

8. Stepanenko I.P. Fundamentals of Microelectronics: Textbook for universities. - M .: Owls. Radio, 1980 .-- 424 pp., ill.

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Claims (4)

1. A method of manufacturing an optoelectronic microassembly containing a housing with digital integrated circuits mounted on its glass substrate, the corresponding information output and input buses of which interact by means of pulsed light radiation propagating from LEDs to photodiodes, including a topological calculation of the mounting positions for placement of microcircuits, LEDs and photodiodes on the upper mounting surface of the substrate and the geometric dimensions of the pads and electrical conductors between them, the manufacture of a glass substrate with polished surfaces, the application of thin-film contact pads and electrical conductors between them on the upper mounting surface of the substrate, the installation of microcircuits, LEDs and photodiodes on the corresponding seats on the upper mounting surface of the substrate and the installation of the substrate in a microassembly, that when performing a topological calculation, additionally determine the location on the upper and lower surfaces of the mirror substrate with a reflective surface facing the glass, and intended to reflect the beam of electromagnetic light radiation propagating in accordance with the optical connection scheme through the glass substrate from the LED to the interacting photodiode, and the angles of incidence of the radiation beams on the substrate for each LED spot optically associated with appropriate photodiodes, after the manufacture of a glass substrate with polished surfaces is applied to its upper and lower surfaces of the mirror and in accordance with the results of calculation of mirrors topological locations on the substrate surface after application on the upper surface of the substrate the thin film pads and electrical conductors between the glass substrate is subjected to electromagnetic radiation toning ray or gamma radiation dose of 10 ² to 10 ⁴ Gy, then passed through the a glass substrate in series through each of the LED seats, beams of a sharply focused pulsed or continuous laser image atyvayuschego radiation at respective angles of incidence on the glass with a focal length many times greater than the length of the substrate, with an energy of 25-50 mJ for a time sufficient to form a transparent glass substrate the light transmission of the communication channel between the respective pair of interacting LEDs and photodiodes. 2. The method according to claim 1, characterized in that the mirrors are applied to the lower and upper surfaces of the substrate discretely in accordance with the results of a topological calculation of the locations of the mirrors on the lower and upper surfaces. 3. The method according to claim 1, characterized in that a continuous mirror layer is applied to the lower surface of the substrate, and mirrors are applied discretely to the upper surface of the substrate in accordance with the results of topological calculation of the locations of the mirrors on the upper surface of the substrate. 4. The method according to claim 1, characterized in that the mirrors used are deposited by thin-film technology metal, for example, aluminum.

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